Automatic chuck



March 39, 1946. J. MacBLANE 9 3 AUTOMATIC CHUCK Filed May 23, 1944 Patentecl Mar. 19, 1946 AUTOMATIC CHUCK James MacBlane, Elmira Heights, N. Y., assignor to Bendix Aviation, South Bend, Ind., a corporation of 'Delaware Application May 23, 1944, Serial No. 536,?)9-0 2 Claims.

The present invention relates to an automatic chuck and more particularly to a device for gripping and holding a part to be machined which device is automatically closed as'a tool is brought up to the work, and released when' the tool is backed away.

It is an object of the' present invention to provide a novel automatic chuck which is efficient and reliable in operation and simple and economical in Construction.

It is another object to provide such a device in which the work is lined up and gripped with a substantially uniform pressure prior to engagement of the tool.

It is a further object of the invention to provide such a device which grips the work quickly and positively, without the use of levers, wrenches or other tools for its operation.

It is another object to provide such a device which automatically ejects the work from the chuck when the tool is backed away from the work.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing, in which:

Fig. 1 is a side elevation partly in section of a chuck formed in accordance with the present invention, with a work piece therein and a facing tool Operating on the work; and

Fig. 2 is a detail in perspective partly broken away of the sliding jaw members of the chuck.

In Fig. 1 there is illustrated a socket member l which is adapted to be mounted in the live head of a lathe, not illustrated. lfhe socket member has a tapered or outwardly flared opening 2 which terminates in a cylindrical recess 3, and a plurality of tapered jaw members 4, 5 and 6 whose outer surfaces conform to the tapered opening 2, are slidably mounted therein and are retained by suitable means such as a flanged ring 'I threaded on the end of the socket member l. Means normally 'urging the jaw members outwardly to open the jaws is provided in the form of a spring 8 seated in the recess 3 and hearing on the inner ends of the jaws. Rotation of the jaws in the socket member i is prevented by suitable means such as a stud 9 threaded in the socket member so as to project into a grccve formed by rabbeting the adjacent surfaces of jaws 4 and 5.

The inner surfaces of the jaws 4, 5 and 6 are ormed to engage the exterior surface of a work piece ll, said inner surfaces being threaded so as to grip the work piece and resist relative longitudnal movement. The outer surfaces of the jaws 4, 5 and 6, are tapered at such an angle that the jaws will not jam or stick in the opening 2 of the socket member, but will slide freely outward under the action of spring 8 when permitted to do so, thus releasing the grip on the work piece. A suitable non-jamming angle of taper which has i been found satisfactory is an included angle A of 25 as indicated in Fig. l of the drawing. The inner surfaces of the jaws are formed with a low angle such as 10 for example of taper so that the jaws will grip the work tightly and prevent movement of the work in the j aws. Entry of the work into the jaws is limited by engagement of shoulder !2 of the work piece against the outer ends of the jaws.

A tool holder 13 is adapted to be mounted on the tool slide of the lathe, not illustrated, whereby the tool ta here shown as a racing tool, may be moved longitudinally into engagement with the end of the work piece. The work piece has a cupshaped opening l5 in its outer end, and the tool holder 13 carries a plunger !6 slidably mounted therein in position to enter said opening. Spring means l'l in the work holder is provided for yieldably projecting the plunger so that it engages the work piece and presses it into the chuck as the tool holder is brought up to the work. The spring I'I is sufiiciently stiff to cause the work and the jaw members 4, 5, 6 to be moved into the socket member l against the force of the spring 8 where by the jaws are caused to grip the work and hold it rigidly prior to engagement of the tool therewith.

When the tool M engages the work to perform a facing operation thereon, rotation of the work is permitted by the smooth bearing between the work and the end of plunger !6. If deemed desir'- able, of course, the plunger IB may be provided with an anti-friction thrust bearing.

Means are provided for automatically ejecting the work from the chuck as the tool is backed off from the work. As here shown, this is accomplished by providing an ejector thimble l8 ar- 4 ranged to enter a cup-shaped cavity [9 in the inner end of the work, actuated by a light compression spring 20. Outward movement of the thimble under the action of the spring 20 is limited by engagement of a fiange 2! on the thimble with the inner ends of jaw members 4, 5, 6.

In operation, the jaw members 4, 5 and 6 are normally projected outwardly by the spring 8 until they engage the flanged ring l. The work is inserted in the jaws and the tool holder then brought up toward the work until the plunger !5 engages the work and presses it into the chuck.

desired operation thereon, such movement being g member having a fl-ared opening, a plurality of permitted by compression of the plunger spring ll. When the operation is completed, it is merely necessary to back away the tool holder whereupon the jaws 4, 5, 6 are opened by the action of spring 8, and the work is ejected therefrom by the spring-actuated thimble !8. The parts are then i in position to repeat the operation.

Although but one embodiment of the invention has been shown and described in detail,it will be member having a tapered opening, a plurality of exteriorly tapered jaw members slidably mounted therein, yelding means urging the jaws out of the opening and means for limiting their outward movement; and a tool holder having means for yieldingly engaging a work piece in said jaws and pressing it into the chuck as the tool approaches the work, the means for pressing the work into the chuck comprising a spring actuated plunger slidably mounted in the tool holder in position to engage the work prior to the engagement of the tool carried by the holder.

2. In an automatic chucking device, a socket jawmembers conforming to said opening and slidably mounted therein to thereby grip a work piece inserted in the jaws, means limiting out- Ward movement of the jaws, movable means for holding a tool in position to operate on the work, and means carried by the tool holding means for pressing the work into the socket, the jaWs being so formed as to hold the work without slippng, whereby the jaws and work slide together in the socket member; including further a thimble in the chuck adapted to engage the work, and a spring for actuating the thimble to eject the work when released by the jaws, said thimble having a flange adapted to engage the inner ends of the jaws to limit outward movement of the thimble.

JAMES MACBLANE. 

